A materials mystery: What the heck are "self-healing" cutting mats made from? And a possible alternative

The other day one of my students asked me what a self healing cutting mat is made of. I have done a search and only found the mysterious phrase "made of a unique self healing composite material". Does anyone know what they are made of?

None of the respondents (or Google, for that matter) had the answer, and a few pointed out that the "self-healing" description is a bit of marketing spin, to which most of us can attest; the "self-healing" cutting mats I used at school all looked like Federal informants someone had failed to assign guards to.

In response to yesterday's post on cutting mats, a reader named Adam opined that UHMW (Ultra-high-molecular-weight) Polyethylene would be a good substitute. UHMW is a tough, low-friction, largely chemical-resistant thermoplastic often used for industrial-sized food-processing surfaces. It's more abrasion-resistant than carbon steel and is used for pickup truck beds, the bottoms of skis (because gouges can be easily filled and repaired), and if you've ever seen those skateboarding gloves with the plastic bits that downhillers can use to place their hand on asphalt whipping by beneath them, that stuff is UHMW too.

I'm not certain that's what cutting mats are made of, only because UHMW is odorless and every cutting mat I've used had a strong vinyl smell; then again cutting mats are usually three layers, a rigid core bookended by layers of softer stuff, so perhaps the vinyl smell comes from the center layer, and perhaps you can do without it.

I tried 1/16" HDPE (High Density Polyurethane) sheet (48" by 96") which someone in another forum recommended but it dulled my rotary cutter blade after just a few cuts. There were deep cuts in the HDPE as well. Very disappointing!

I had this post tucked away in my brain for future reference. Now that I feel the need for a cutting mat, I'm disapointed to find out that no one has found a good inexpensive source of cutting mats. However, I did find the URL above (click my name) which has an expanded diagram of a mat. By the looks, this isn't something one can DIY.
TL;DR: cutting mats are multiple layers of PVC with different hardnesses.

If the mats were really "self-healing" then you could cut a chunk off the corner, hold it in place place with tape and then at some later point, the corner would have re-attached itself (like Blu-tak or the T-1000). Better yet, if it was really self-healing, it would re-grow the corner itself (like a lizard can regrow its tail) :)
The actual "self-healing" behaviour is the same as if you were to cut on a thick rubber mat - the cut is still there, but the material is soft enough that the cut becomes invisible if there's nothing prying it open. Try flexing your cutting mat and you should see some of the old cuts open up again.
The hard board is there because cutting on soft stuff sucks, as you would know if you've tried cutting on carpet before. Cutting on hard surfaces is preferable, because then there's less friction between the surface and the blade (again, think of cutting on rubber, as the blade sinks in, the rubber grabs on to the side of the blade). Problem is, hard surfaces blunt your blade, and it's harder to apply pressure to the thing you're trying to cut to make sure the cut is clean - ideally the blade goes all the way through what you're trying to cut.
So the top layer of a cutting mat is a thin layer of soft plastic. Beto mentioned PVC - probably correct - the finish feels like vinyl toy figurines - warm and soft with a satin-type finish. You can add plasticisers to PVC to make it as soft or hard as you like - for example if you have headphones, the cable is likely sheathed in soft PVC. The hard core of the board means that your blade doesn't sink too far into the soft material, which would increase friction, and makes it harder to bend the board, which as a bonus makes it harder to show that it's not really self-healing ;). And if the base is another soft layer (I have some that are, some that aren't), then it's probably a bonus cutting surface, but it also means the mat is less likely to slip.

This is a great question, and kudos to you for asking it. I'm passing the question on to my readers at Make: Online.
And for the record, I have an advanced degree in organic chemistry, and I don't know. And I once took a seminar class from a chemist whose work in self-healing polymers is highly respected, and when I asked him about self-healing cutting mats, he was shocked to even learn that there were self-healing plastics on the market at all. He had no idea what they were made of.
And as to the idea that designers should stick to designing and engineers to engineering, I respectfully disagree. We're all better off if everyone, everywhere, understands everything better. Keep asking these questions, and don't be afraid to propose answers.

Yep, and Titanium cutting boards are even more resistant to damage :P
Come-on people think about the cost of good steel blades (you did know rusty old steel gives a better edge than Stainless etc. didn't you.) In my experience blade cost far outweighs board cost.
I stand by my plausible post in answer to the original question; imagine you are looking down on a mat made of toothbrush fibers filled with chewing gum. Many cuts bypass the structural fiber but occasionally (e.g. a cut angled non-perpendicular to the surface) cuts the fibers and you get a scar.
I've always guessed its a composite.

UHMWPE will deform fairly easily under a sharp pressure, so thin sheet will be fairly easily cut. its usefullness is that it is fairly tough and has low friction, hence its use (in greater thicknesses) as a shield against abrasion or as a bearing surface (eg. in medical implants). HDPE (ie. less dense and cheaper version of polyethylene than UHMWPE) food chopping boards are very common - better to try them?
If you want to go nuts, maybe try PEEK...
...and this article highlights one of my main problems that crop up with core77: 'designers' with little 'engineering' knowledge. 'designers' need to engineer, 'engineers' need to design.

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